Since carbon dioxide is a major cause of global warming, a reduction in its discharge and effective utilization of it have been regarded as urgent requirements in recent years.
In addition, despite being generated in the technical fields of petroleum refining, petroleum chemistry, and the like, various hydrocarbon gases cannot be always efficiently utilized as feedstock gases for various substances, and a method for converting hydrocarbon gases into more effective substances has been desired.
Under the circumstances described above, a method in which a saturated hydrocarbon, such as methane, functioning as a reducing agent, is reacted with carbon dioxide in the presence of a catalyst so as to realize into hydrogen and carbon monoxide which are industrially effective synthetic gases (carbon dioxide reforming of a hydrocarbon) is known.
As a catalyst used for carbon dioxide reforming of a hydrocarbon, a catalyst in which nickel, ruthenium, or rhodium is supported on a carrier such as alumina or silica is known (see Patent Documents 1 and 2).
However, carbon deposition is likely to occur on the catalyst when the catalyst in which nickel, ruthenium, or rhodium is supported on a carrier such as alumina or silica described above is used, and there is a problem in that the surface of the catalyst is covered by the deposited carbon and activity is decreased, and that the reaction vessel becomes clogged by the blocking of the space between catalyst grains.
In addition, in the synthesis of DME (dimethylether) and the step of manufacturing liquid fuel or alcohol by the OXO synthesis process that are considered as uses of the manufactured synthetic gas, the synthesis process is generally performed under pressurized conditions. Therefore, in order to omit the need for repressurizing the synthesis gas obtained by carbon dioxide reforming, it is desired that carbon dioxide reforming is also performed under pressurized conditions.
However, when the conventional catalyst in which nickel, ruthenium, or rhodium is supported on a carrier such as alumina or silica described above is used, operation under pressurized conditions causes more significant carbon deposition than the operation under atmospheric pressure conditions.    Patent Document 1: Japanese Patent Application Laid-Open No. 8-231204    Patent Document 2: Japanese Patent Application Laid-Open No. 9-168740